The present invention generally relates to a projection type image display apparatus for projecting an image of an image display element on a projection plane such as a screen by enlarging the image so as to display the image. More specifically, the present invention is directed to a projection type image display apparatus in which the projection distance between a screen and the projection type image display apparatus is short.
Various sorts of projection type image display apparatuses have already and practically been utilized by which images of image display elements are displayed on screens (projection planes) in enlarge modes via projection optical units constructed by employing a plurality of lenses.
Since these projection type image display apparatus display images by projecting light of images on screens, these projection type image display apparatuses are suitable for display images on large-sized screens. Also, since projection type image display apparatuses need not be connected to screens by cables, there is such a feature that degrees of freedom for setting the image display apparatus become high. However, although the setting degrees of freedom are high, directions of projection light are required to be adjusted. Generally speaking, directional adjustments of the projection light are carried out by screwing screw-type legs which are provided on bottom portions of projection type image display apparatuses.
For instance, JP-A-2006-330757 has disclosed a projection type image display apparatus, tilts and heights of which are adjusted by legs equipped with first adjusting means and second adjusting means. The first adjusting means adjusts projection amounts of the legs in a stepwise manner, and the second adjusting means adjusts the projection amounts of the legs in the arbitrary manner. Further, JP-A-2006-227050 has disclosed a technical idea that the lens cover provided on the tip of a projection lens is employed as the leg of the projector and the tilt mechanism thereof.